AUDI A4 1995 B5 / 1.G ATQ Engine Ignition System Checking User Guide

28-9


- In order to perform a resistance measurement, connect multimeter
between both ignition wire connectors connectors of the ignition coil to
be checked.

Specification: 8 to 14 k
- In order to perform a resistance measurement, connect multimeter
between both ignition wire connectors connectors of the ignition wire to
be checked.

Specification: 3 to 7 k
- Replace faulty components if the specified values are not reached
again.
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28-10

Checking Ground (GND) supply of power
output stage

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
2 B+

LED must light up.
- Check the wire connection for open circuit:
- Repair open circuit if necessary.
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28-11

Checking voltage supply to ignition coils

Note:
Voltage is supplied to ignition coils via Fuel
Pump (FP) relay.

Test requirement:

Fuse for ignition coils OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

If LED does not light up: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Engine Ground (GND)
- Operate starter.

LED must light up.
- Check the wire connection for open circuit:
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Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Repair open circuit if necessary.
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28-12

Checking activation

- Disconnect connectors from all six fuel injectors.
(afterward check DTC memory)

If specified values are not obtained: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
3 Engine Ground (GND)
4 Engine Ground (GND)
5 Engine Ground (GND)
- Operate starter for a few seconds.

LED must blink (brief blink signal).
- Switch ignition off.
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM Page 24
-17
.
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28-13


If no malfunctions are found in wires: - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
3 102
4 103
5 94
- Repair open circuit or short circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-21
.
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28-14


Intake Air Temperature (IAT) sensor -G42-,
checking

Special Tools and Equipment

VAG1526A
VAG1594A
VAG1598/31
VAS5051 with VAG5051/1
- or
VAG1551 with VAG1551/3B
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28-15
Component location Overview of Component
Locations, page Page 24
-5

Test sequence

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Ignition must remain switched on for this.Rapid data transfer
HELP
Select function XX

When indicated on display:
- Press buttons -0- and -8- to select "Read Measuring Value Block" and
press -Q- button to confirm input.
Read Measurin
g Value Block
Q
Input display group number XXX

When indicated on display:
- Press buttons -0-, -0- and -4- to select "display group number 004" and
press -Q- button to confirm input.
Read Measuring Value Block 4
1
2
3
4

Indicated on display:
- Check specified value for Intake Air Temperature (IAT) sensor in
display field 4:
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28-16


Display fields

1 2 3 4
Display group 004: Intake Air Temperature (IAT), engine at idle
Display xxxx/min xx.xxx volts
xxx.x C
xxx.x C
Indicated Engine speed
(RPM) Battery voltage Coolant
temperature Intake Air Temperature (IAT)
Functional
range 630 to 6800 RPM 10.000 to 15.000
V -48.0 to 143.0 C
-48.0 to 143.0 C
Specified value xxxx/min 12.000 to 15.000
V 80.0 to 110.0 C
From ambient temperature up to 120
C
1)
1) Approximate values: While driving, up to 24 C above ambient temperature. If heated while standing, up to 120 C is
possible.
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28-17

Checking wire connections

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
1 85
2 108
- Check both wires to each other for short circuit.
- Repair open circuit or short circuit if necessary.
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